Regular phantom black holes as gravitational lenses

TL;DR

This paper investigates how regular phantom black holes act as gravitational lenses, deriving analytical formulas for relativistic images and comparing results with other black hole models.

Contribution

It introduces a new analysis of regular phantom black holes as gravitational lenses, providing explicit formulas for image positions and magnifications in the strong deflection limit.

Findings

Analytical expressions for relativistic image positions and magnifications.

Comparison with Schwarzschild and Brans-Dicke black holes.

Potential observational signatures of phantom black holes.

Abstract

The distortion of the spacetime structure in the surroundings of black holes affects the trajectories of light rays. As a consequence, black holes can act as gravitational lenses. Observations of type Ia supernovas, show that our Universe is in accelerated expansion. The usual explanation is that the Universe is filled with a negative pressure fluid called dark energy, which accounts for 70 % of its total density, which can be modeled by a self-interacting scalar field with a potential. We consider a class of spherically symmetric regular phantom black holes as gravitational lenses. We study large deflection angles, using the strong deflection limit, corresponding to an asymptotic logarithmic approximation. In this case, photons passing close to the photon sphere of the black hole experiment several loops around it before they emerge towards the observer, giving place to two infinite sets of relativistic images. Within this limit, we find analytical expressions for the positions and the magnifications of these images. We discuss the results obtained and make a comparison with the Schwarzschild and Brans-Dicke solutions for the case of the galactic center supermassive black hole.